California recently rolled out its early warning system throughout the state, including in San Diego.
The so-called ShakeAlert warnings are being pushed through two delivery systems: a cell phone app called MyShake and the same wireless notification system that issues Amber Alerts.
This is great news. The early warning system operates on a network of underground sensors that detect seismic activity and send out warnings that will allow people to duck and cover. Elevators can be stopped at the nearest floor and open before a quake hits, subways and rail transit can come to a halt, surgeons in hospitals will know to wait before making an incision.
All of this is designed to save lives by giving people early warnings and a little time to prepare. Unfortunately, these warnings will do nothing to actually protect buildings and infrastructure from damage from the quake. Only structural engineering retrofits can strengthen these structures to make them more seismic resilient and truly protect them and people during earthquakes.
Why is Protecting Buildings Important?
San Diego, while not so much at risk as Los Angeles or San Francisco, still faces the potential for significant building damage in a quake.
The Rose Canyon Fault runs right through the middle of the city — from the Silver Strand to La Jolla — snaking its way under lofty sky scrapers, commercial districts and apartment buildings that draw tens of thousands of people each day.
Seismologists agree that Rose Canyon, while relatively inactive, has the capacity for a 7.0-magnitude quake similar to that experienced recently in Ridgecrest. When it does strike, the damage caused could be colossal: at between $124 million and $13 billion, according to experts.
That’s because San Diego is more heavily populated than Ridgecrest — and a large portion of its buildings were constructed based on outdated and ineffective codes.
In fact, the California Geological Survey ranks San Diego as one of the state’s top 10 areas for projected loss from an earthquake.
Studies Show Cost Benefits of Retrofits
Researchers at Caltech have determined that for every dollar spent in retrofitting soft-story structures, property owners could expect to save up to seven dollars in quake damage, and that study didn’t factor in loss to contents, alternate living expenses or deaths and injuries – all of which would have significantly increased the cost-to-benefit ratios.
In a separate study, the university determined that seismic retrofits are cost-effective when projected annualized loss would be reduced by 50 percent or more at a cost that would equal no more than 10 percent of the replacement cost of a building.
There are other strong economic factors to consider when weighing the cost benefits of a seismic retrofit. These include potential loss of income and liability associated with damage, death and injury resulting from an earthquake.
Loss of income can occur when commercial property is damaged to the point where it is no longer habitable. This can create severe financial hardship for property owners who not only lose their monthly rental income, but simultaneously face the costs of repair and recovery coupled with ongoing monthly payments associated with their original mortgage.
There are liability risks as well. A precedent-setting case in Paso Robles found building owners negligent for maintaining a hazardous condition and liable for the deaths of two workers killed in an earthquake in 2003. A state appeals court upheld the verdict in 2010 setting the precedent that it doesn’t matter if a quake is an “act of God” or that the building in question technically complies with city building codes. Just knowing a structure is unsafe and not taking corrective action is grounds enough to assign blame through negligence, the courts found.